Differential pliers.



N0. 808,206v PATENTED DEG.26,1905.

J. L. KNIGHT.

DIFFERENTIAL PLIERS.

APPLICATION IILEDIIIAR.7,1904.

FIG.1.

Wrrmzssss. INVENTOR.

UNITED STATES PATENT @FFICE JONATHAN LEE KNIGHT, OF NATIONAL MILITARY HOME, KANSAS, ASSIGNOR TO ASAHEL U. MORSE, OF KANSAS CITY, MISSOURI.

DIFFERENTIAL PLIERS.

Specification of Letters Patent.

Patented Dec. 26, 1905.

Application filed March 7, 1904. Serial No. 197,012-

TO all whom it may concern;

Be it known that I, JONATHAN LEE KNIGHT, a citizen of the United States, residing at National Military Home, in the county of Leavenworth and State of Kansas, have invented certain new and useful Improvements in Differential Pliers, of which the following is a specification.

My invention relates to improvements in pliers in which circular motion over radial lines by the handles is converted into motion of the jaws along lines parallel to the diameter-line of a circle of which the center is the point where the handles cross and are pivotally connected, their fulcrum-point as levers.

The object of my invention is to produce parallel-j aw pliers by mechanism which shall afford a degreeof automatic adjustability in the movement of the jaws, whereby they may clamp objects having parallel sides or frustum-shaped objects regardless of whether the straight lines of the jaw-faces converge in front or in the rear of the fulcrum-point of the handles. I attain these objects by means of the mechanism illustrated in the accompanying drawings, in which Figure 1 is a plan view of my improved pliers with the jaws closed, their straight clamping-faces in contact. Fig. 2 is a plan view of the pliers, a part of the handles being omitted, in which the jaws are opened, their clamping-faces being parallel to each other. Fig. 3 is a plan view of the pliers, part of the handles being omitted, in which the jaws are partly opened, their faces being radial, and clamping a frustum-shaped object with base in rear of the fulcrum-point of the handles. Fig. 4 is a plan View of the link, which by reason of its novel form in having an opening at its outer end 6 somewhat larger than the journal operating in said opening becomes, in effect, an eccentric or differential gear. Fig. 5 is a cross-sectional view of the pliers, taken on the line y y of Fig. 1. Fig. 6 is a cross-sectional view of the pliers, taken on the line 00 w of Fig. 1. Fig. 7 is a differential diagram showing the direction and extent of the movements of definite points of the mechanism when the same is in operation.

The problem to be solved is not the mathematically-impossible one of squaring the circle, but the more practical and useful one of converting circular motion over radial lines,

produced by revolving the handles of a pair of pliers round their pivot-point, into motion of the jaws of the tool along parallel lines or radial lines of variable increment converging on either side of the fulcrum or pivotpoint of the handles. It must also be understood that this adjustment or variation in direction of the lines to which the jaw-faces are to be brought shall be entirely automatic, to the end that the power applied on the handles as levers shall be transmitted to the jaws in such manner that their movement will confrom to the shape of the object being clamped between them whether such obj ect have parallel sides or be frustum-shaped. In describing the mechanism by which these results are attained the three essential ele ments of the invention are indicated by letters.

In the drawings, A represents the aws, B represents the handles, and 0 represents the eccentric link. A indicates a depression in the sides of the jaws in which the links move, being as deep as the thickness of the links.

In Fig.- 1, 1 is the central rivet-hole in the handles, their fulcrum-point as levers where they cross each other and are pivotally connected by the rivets 8. 2 is the front rivethole in the handles, where they are pivotally connected to the front portion of the jaws by the rivets 7, which pass through the jaws, as well as the outer ends of the handles. Power applied on the long arms of the levers or han-. dles is transmitted through this pivotal connection at their short arms to the jaws,where it is applied in clamping the object to be held by the pliers. 3 is the rear rivet-hole in the handles, and 10 is the headed rivet, by which the inner end of the eccentric link is pivotally attached to the handles. 4 is the stop rivet-hole in the handles, and 9 is the rivetbolt rigidly fixed therein extending from side to side of the U-shaped handles and having the double function of a brace to the handles and a stop or limit to the opening movement of the jaws.

In Fig. 2, also all of Fig. 4, O is the eccentric link, having at its inner end the small opening 5, whereby it may be pivotally connected to the handles, and at its outer end the larger opening 6, in which the projecting journal end of the bolt 11 loosely plays. This bolt 11 passes through and is rigidly fixed in the jaw, with its ends projecting across the depression A, through the opening 6 of the link, and against the inner sides of the handles.

In Fig. 5, B shows a cross-section of the U- shaped handles at the line y 1 of Fig. 1, and in Fig. 6 their flat form at the line 00 00.

In Fig. 6, 12 is the opening through the rear end of the jaw, in which the bolt 11 with 1ts journal ends projecting is rigidly fixed. On these journal ends the link 0 is loosely supported. The ratio of difference in the diameters of these journals and the diame ters of the openings 6 in the links measures the extent of the automatic adjustability in the movement of the jaws.

In describing the diagram Fig. 7 the terms point anc points are used, and these are indicated in the drawings by reference-letters. In the other figures the positions of these points have been indicated by reference-numerals and shown in the draw in gs as openings or rivets. The term point as now used will indicate the center of the rivet or opening, as hereinbefore described.

In Fig. 7, a, a represent the general base-line, from which the direction, extent, and increment of the different movements are computed. I) b are base-lines on which are situate the centers from. which the radial lines g g extend to the pointsff. e is the central pivotpoint where the handles cross. (Z (Z are the points where the jaws are pivotally connected to front ends of the handles. 6 e are the points where the links are pivotally connected to the handles. are points where center of the journal ends of the bolt 11 are located, being where the links are connected to the handles. 9 g g g are the radii from which the arcs h h h h are struck. j j are the arcs described by the points 6 6 when handles are moved over the radial lines 7c 7c. The solid lines show positions of the several points when the jaws are closed, having their faces in contact at the base-line a a. Dotted lines show positions of the same points when jaws are fully opened and with their faces parallel to each other and the baseline. The links extend between the points 6 e andfwhen jaws are closed and between same points on dotted lines when jaws are fully opened. The radial lines g g are equal to the radial lines 9 g. The lines passing through the points (1 (Z are the same distance vertically from the base-line a a as are the points f f vertically distant from the baselines I) Z). Hence it follows that the arcs h It and the arcs h h are equal each to each. The radial lines 76 7c have a length about ten per cent. greater than the lines 9 g g g. The points e e are approximately but nine-tenths the distance from the base-line a a as are distant the points (Z d. Hence the arcs j j differ from the arcs h 72 in many respects. They 5 are struck from longer radii. They begin 2 nearer the base-line, hence are less deflected from their tangents drawn vertical to the baseline. Measured by degrees the arcs j are but about seventeen degrees, while the arcs it h and 7t 7t are about twenty degrees of their respective circles, yet of the points (Z (Z, c e, and f f traversing these diverse arcs each moves the same distance, measured vertically, from the base-line or center from which. the arcs were struck. As the arcs 72/ h differ from the arcs in degrees of length, deflection from their tangents, length of radii, and curve in opposite directions, it follows that their points of beginning 6 and f, being the same distance apart, if connected by a rigid link of definite length could not traverse these arcs at same time, though when the jaws are fully opened both points are found on the arcs the same distance apart as when jaws were closed and also the same and equal distances from their base-lines. To allow these points to so change positions from the solid to the dotted lines, their connection, while in substance a link, in effect, becomes a differential gear by reason of the fact that the opening 6 in its outer end has a diameter as much greater than the diameter of the journal end of the bolt 11, on which it turns, as is required to allow the point f to diverge from its arc and in effect lengthen or shorten its connectinglink, thereby not only allowing the movement to be made, but also giving automatic adjustment to the jaws, whereby their straight clamping-faces being parallel when in contact may remain so until fully opened, or at any intermediate point the faces of the jaws in clamping an object with sloping sides will automatically take positions on radial lines, as shown in Fig. 3. This feature, converting a link into a differential by making one of its openings larger than the journal which turns in it, forms the essence and fundamental principle of the invention, as by it the movements of the device are not only made possible, but the computation of the increments of motion involved by the use of the group of arcs, chords, and tangents affords the basis of mechanically utilizing the principle in accomplishing all the proposed objects of the inventionviz., the supplying of a parallel-jawpliers automatically adjustable within certain limits by which tool objects with. either parallel or sloping sides may be firmly clamped.

It may be added that while the ratios or proportional lengths of the several radii andarcs as herein given have been found by practical experience and demonstration to accomplish the results described and are believed to be approximately what would be found convenient in the tool as made for general use these ratios and dimensions may be varied to give a greater or less degree of adjustability without departing from the scope or spirit of my invention. It may also be said that the increment of the difierential may be varied by a change of ratio between the diameter of the journal end of the bolt 11 and the diameter of the opening 6, in which it moves. This difference, however, must always be enough to allow the points 6 and f to move from end to end of their arcs by such slight deflection as to, in efiect, lengthen or shorten their connecting-link, for the reason that if required to be the same distance apart at all positions of the movement they could not follow the arcs nor give the differential to the movement of the jaws.

Having thus fully described my invention, the details of its construction, and the manner of its operation and use, what I claim as new, and desire to secure by Letters Patent of the United States, is

1. A differential pliers, comprising intersecting handles pivoted together, a jaw eX- tending forwardly and rearwardly of such pivotal point and pivoted to the front end of one of said handles, a second jaw similarly arranged with respect to said pivotal point and pivoted to the front end of the other handle, and means for connecting the rear portion of each-jaw with the handle pivotally carrying the companion jaw; said means having differential or lost motion with respect to the aws.

2. A differential pliers, comprising intersecting handles pivoted together, a jaw ex tending forwardly and rearwardly of such pivotal point and pivoted to the front end of one of said handles, a second jaw similarly arranged with respect to said pivotal point and pivoted to the front end of the other handle, and links pivotally connecting the handles with the jaws rearward of the pivotal point of the former and having differential or lost movement with respect to the jaws.

3. A difierential pliers, comprising intersecting handles pivoted together, a jaw eX- tending forwardly and rearwardly of such pivotal point and pivoted to the front end of one of said handles, a second jaw similarly arranged with respect to said pivotal point and pivoted to the front end of the other handle, means for connecting the rear portion of each jaw with the handle pivotally carrying the companion jaw; said means having differential or lost motion with respect to the jaws, and stops to limit the outward movement of the rear ends of the jaws.

4. A difierential pliers, comprising intersecting handles pivoted together at their intersection-point, a jaw pivoted between its ends to each handle and provided rearward and outward or its pivotal point with a rigid cross-pin, and links pivoted at their inner ends to the handles and engaging and having lost motion with relation to the pins rigidly carried by the jaws.

5. A differential pliers having intersecting handles pivoted together at their intersection-point and provided with inwardly-projecting pins rearward of their pivotal point, a jaw pivoted between its ends to each handle and provided rearward and outward of its pivotal point with a rigid cross-pin, links pivoted at their inner ends to the pins of the handles and having holes in their outer ends of materially greater diameter than and engaging the rigid pins of the jaws to permit the latter to move a'limited distance without affecting the positions of the links.

6. A differential pliers, comprising handles having their front portions bifurcated and their rear portions of hollow form, alined pivots uniting the bifurcated portions of the handles, jaws extending forward and rearward of said pivots within said bifurcations and each pivoted to the, front end of one of said handles, stop-pins carried by the handles to limit the outward movement of the rear ends of the said aws, pins carried by the rear portion of said jaws, and links interposed between the handles and the jaws and pivoted at their inner ends to the former and provided at their outer ends with holes loosely receiving the pins of the jaws.

7. In a parallel and radial moving jaw pliers, the combination of the straight-face jaws, A, the hollow handles, B, the eccentric link, 0, the fixed journal-bolt with projecting ends, 11, the stop and brace bolt 9, and the bisected pivot-fulcrum rivets, 8, all cooperating in the manner and for the purposes as shown and described.

In testimony whereof I affix my signature in the presence of two witnesses.

JONATHAN LEE KNIGHT.

Witnesses:

FRANK A. SPENCER, NATHAN DAVIS. 

